This invention relates to amorphous bulk materials useful in chewing gum and more particularly relates to low water content amorphous polyol bulk material and chewing gum incorporating such bulk materials.
Typically, chewing gum contains a water-insoluble gum base component usually containing an elastomer and an inorganic filler such as calcium carbonate, a water-soluble bulk material or “bulking agent” component, and minor components such as flavors, colors, and sensates. The conventional bulking agent is sugar (sucrose) which provides bulk and appropriate sweetness to a chewing gum composition. “Sugar-free” gum compositions typically replace sucrose with a polyol as a bulking agent. Because polyols are not as sweet as sugar, such “sugar-free” gums also contain high intensity sweeteners such as aspartame or sucralose.
Consumers prefer a chewing gum that has a firm, but not too hard, chewing character from the first bite though the final chew. They also want the same chew texture character whenever they use the product. Because traditionally chewing gum is 20-80% bulk sweetener, the bulking agent physical form influences the chewing gum texture.
Typical sugar-free chewing gum products contain bulking agents that are in a crystalline powder form. Traditionally, sugars are hydrogenated into polyol solutions, which then are crystallized and purified into crystalline bulk powders, usually contain only a single polyol. The crystalline polyol powder then is mixed with the gum base and other ingredients, such as softeners, flavors, colors and sensates. Addition of crystalline polyol powder to chewing gum requires a handling system with dust control together with bulk dry storage and transport systems.
During mixing, powder material aids in breaking up the chewing gum base mass, allowing intermixing with the other chewing gum components. Too much bulk material, when on powder form, can lead to brittle, non-elastic chewing gum mass. Too little bulk material powered can lead to sticky, deformable chewing gum mass. Additionally, the size of the powder crystal also may affect the texture of the chewing gum. Finer crystal powder is traditionally used so as to not give a brittle and/or gritty texture. Moisture can initiate crystal growth, creating a change in the chewing gum texture during storage.
The bulk material (sometimes referred to as the “bulking agent”) gives mass to a chewing gum and modifies the chew of the gum base. Bulk material often gives sweetness to the chewing gum, although sweetness often is boosted by addition of high intensity sweeteners. The bulk material also carries flavors and other minor soluble ingredients into the saliva as the chewing gum is chewed. The bulk material affects the texture of the chewing gum during processing (such as sheeting), during chewing (such as with the first bite), and during storage (controlled texture through controlled physical structure). The most common bulk material for sugar-free chewing gum is sorbitol, due to its lower cost than other other polyols, such as maltitol or xylitol. Other polyols include mannitol. As cost is among key criteria in choosing sorbitol, there is a need for a less expensive version of sorbitol for use as a bulk material for sugar-free chewing gum.
Aqueous sorbitol solution has been added as a partial replacement for bulk crystalline sorbitol powder. Use of sorbitol solutions may be less expensive than sorbitol powder, because such process does not include a crystallization step. Limits to sorbitol solution addition for this purpose have been due to the amount of water in the sorbitol solution, due to the need for a means of getting the sorbitol to crystallize out of solution so that the sorbitol can function as the bulk ingredient. The amount of sorbitol solution addition is limited by the water in the solution. A higher concentrated aqueous sorbitol solution delivers a higher ratio of sorbitol to water. This supersaturated solution will crystallize in the chewing gum mass upon high shear mixing and/or crystal seeding. Anticrysallizing agents, such as glycerin, are added to the supersaturated solution to keep the sorbitol from crystallizing before mixing.
Traditionally, glycerin and/or sorbitol aqueous solution are added to chewing gum for the purpose of softening chewing gum and to aid in intermixing of ingredients. Useful amounts of sorbitol aqueous solution (typically 30 wt % water and 70 wt % sorbitol) and glycerin as softening agents are limited. With sorbitol solution, too much solution addition will add too much water to the product, causing the gum to be too soft to sheet, causing the gum to have too soft a first bite, and causing detrimental physical and chemical changes during storage. If the sorbitol solution has too high a sorbitol concentration, the sorbitol will crystallize out of solution before incorporation into the gum composition, causing significant difficulties in solution processing, storage, and transport, and in addition to the chewing gum. Certain high concentrations of sorbitol (e.g., 45-65 wt. %) are possible in solution, with the addition of other polyols (e.g., 1-24 wt. % maltitol and/or mannitol), and/or glycerin (e.g., 13-45) to keep the sorbitol from crystallizing out of solution until it is mixed into the chewing gum batch. In these circumstances, sufficient shear is then applied to the chewing gum mass during mixing to crystallize the sorbitol out of solution. Moisture, which is then released from the solution as the sorbitol crystallizes, softens the gum. The glycerin and other polyols then become softening additives in the chewing gum.
With glycerin, too much glycerin addition will cause chewing gum to be too soft to sheet and will create easily deformable pieces, which will be difficult to pan coat. Too much glycerin also creates a too soft first bite and general chew texture. Too much glycerin will cause more incorporation of water from saliva into the chewing gum mass as the chewing gum is chewed, creating a general impression of a softer chew. Glycerin is a strong humectant and can cause chewing gum to pick-up moisture during storage, causing detrimental changes during storage. Glycerin is a strong enough humectant that it will pull moisture through an applied pan coating and into the gum center. The moisture can then soften both the gum and the pan coating.
When glycerin is added to chewing gums with traditional crystalline bulk material powders, especially sorbitol, part of the glycerin is pulled or absorbed into pockets of the crystalline powder and part of the glycerin is free to combine with all of the chewing gum ingredients during mixing. Only the free glycerin is available to soften the chewing gum mass, until the pockets of crystalline bulk agent are solubilized during mastication, and then the full glycerin is available for softening. This creates difficulties in determining amount of glycerin addition for the entire life of the chewing gum, that is, from processing through consumption. With glycerin, too much addition into chewing gum will cause the chewing gum to pick-up moisture during storage, causing detrimental changes during storage. This includes glycerin absorbed and free. Glycerin is a humectant. Glycerin is a strong enough humectant that it will pull moisture through an applied pan coating and into the gum center. Also, being a fluid softening material, too much glycerin will lead to deformities during sheeting and/or pellet coating as the gum mass will be too soft and malleable. Too much glycerin also creates a too soft bite and also causes softer general chew as it causes more incorporation of water from saliva into the chewing gum mass as the product is chewed.
Besides softening the gum mass, some fluid material is necessary in chewing gum formulas to aid in intermixing the various formula ingredients, such as gum base, bulk material, and minor ingredients, such as flavors, sensates, high intensity sweeteners and colors. Fluid material also aids in breaking up lumps of dry ingredients and distributes minor ingredients throughout the chewing gum mass.
A fluid material is flowable, that is, it will flow down an inclined plane at a specific temperature. For chewing gum, a fluid material would preferably flow down an inclined plane at gum mixing or sheeting temperatures, which are typically 40-110 C. Traditionally, glycerin and sorbitol aqueous solution are the fluid materials of choice, though other fluid materials have been explored.
Addition of molten polyols to chewing gum has not been found to be practical. Though fluid upon melting, most polyols (for example xylitol) quickly transition to solid crystalline form as they cool. Though molten sorbitol does not crystallize as quickly as other polyols, it does form a hard solid, which then will crystallize upon mixing shear and/or upon seeding. This physical transformation is again useful for hard crystalline coatings, but no useful as a replacement for tradition gum softeners.
There is a need to use an alternative form of bulk material in chewing gum, such that the alternative form of bulk material will perform the bulking requirements of a bulk material in chewing gum, with the advantages of being less expensive than the use of traditional crystalline polyol powder, and yet create a finished chewing gum texture softness without need of sorbitol solution or glycerin. Additionally, if the alternative form of bulk material is fluid, other detrimental characteristics of crystalline polyol powder can be eliminated, such as plant dust filtration equipment.